摘要
中—晚三叠世的鄂尔多斯盆地沉积了一套优质的砂岩储层,目前对该套砂岩的成因及其空间分布已经有了成熟的认识,然而在中—晚三叠世鄂尔多斯原型盆地的确切边界位置、盆内古地理演化的构造成因机制等问题上依然存在不少争议。本文通过对鄂尔多斯盆内及周缘57个露头及165口钻井的层序地层学与沉积学研究,厘定了鄂尔多斯盆地在中—晚三叠世的边界位置并在层序格架下开展了古地理演化研究,同时探讨了古地理演化的构造成因。研究表明:中—晚三叠世鄂尔多斯盆地的北部边界从内蒙古的达拉特旗向东延伸至山西大同,东部边界应在山西宁武—太原—太谷—永和—河南安阳—开封—登封一线附近,南部边界为北秦岭(NQT)与华北板块的缝合带(陕西西安—洛南—河南栾川—南召沿线以南),西南以六盘山的西部断层边缘为界,西北界位于贺兰山西部断层边缘带,西部边界延伸至河西走廊盆地的西部边界(甘肃马良沟附近)。在中—上三叠统延长组识别出4个沉积旋回(SQ1 SQ4),代表了从起始阶段(SQ1)到最大沉降阶段(SQ2和SQ3)再到后期关闭阶段(SQ4)的湖泊演化过程。中—晚三叠世鄂尔多斯盆地内呈现出北部/东北部的曲流河三角洲沉积体系和南部/西南部冲积扇辫状河三角洲沉积体系汇聚的沉积格局,在空间上表现出明显的南北差异,在时间上呈现出沉积中心的东西破坏分异的演化特征。这种古地貌差异和演化主要受控于秦岭—大别山造山带(QDOB)与兴安岭—蒙古造山带(XMOB)的不同构造演化过程。盆地南部的古地理演化主要受控于QDOB的活动,中—晚三叠世勉略洋闭合驱动的北秦岭造山带活化不仅导致盆地南部陡坡带的形成和盆地东南部古地貌的突变,也导致晚三叠世盆地西南部发育一个分隔内克拉通盆地及西南缘类前陆盆地的水下低隆。盆地西部的古地貌�
The Ordos Basin deposited a large set of high quality sandstone reservoirs during the late Middle to Late Triassic.The sedimentary origin of the sandstone reservoirs and their distribution in the basin are well understood.However,the exact paleoboundary of the Ordos Basin and the tectogenetic mechanism of the paleogeographical evolution of the basin are still unclear.Here,by conducting detailed stratigraphic and sequence analyses of 165 boreholes and 57 outcrops in the Ordos Basin and its surrounding basins,we determined the Middle Late Triassic boundary of the Ordos Basin,and explored the paleogeographic evolution and tectogenesis of the basin.The basin is constrained by the Dalateqi,Inner Mongolia and Datong,Shanxi boundaries to the north,the Ningwu Taiyuan Yushe,Shanxi and Anyang Henan Kaifeng Dengfeng,Henan boundaries to the east,the suture zone between the North Qinling Terrance(NQT)and the North China Block(or the Chenhe Luonan,Shanxi and Nanzhao,Henan boundaries)to the south,and the Malianggou,Gansu boundary to the west.Its northwestern boundary extends along the western margin of the Helan Mountain fault zone.The Middle Upper Triassic Yanchang Formation can be divided into four sedimentary cycles(SQ1 SQ4),representing the lake evolutionary process from the initial stage(SQ1)to the maximum subsidence stage(SQ2 and SQ3)and then to the later closing stage(SQ4).The sedimentary pattern of the Ordos Basin features a meandering river-delta sedimentary system in the north-northeast and an alluvial fan-braided river-delta sedimentary system in the south-southwest,showing obvious N S spatial differentiation and E W temporal differential evolution of depocenter.Our study show that the depocenter migration and paleogeographic differentiation in the basin were controlled by the tectonic evolutions of the Qinling Dabie Orogenic Belt(QDOB)in the south and the Xing anling Mongolia Orogenic Belt(XMOB)in the north.The paleogeographic evolution of the southern basin was mainly controlled by the QDOB activities.The activatio
作者
阮壮
罗忠
于炳松
卢远征
谢灏辰
杨志辉
RUAN Zhuang;LUO Zhong;YU Bingsong;LU Yuanzheng;XIE Haochen;YANG Zhihui(State Key Laboratory of Geological Process and Mineral Resources,China University of Geosciences(Beijing),Beijing 100083,China;Research Institute of Petroleum Exploration and Development,CNPC,Beijing 100083,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2021年第1期12-32,共21页
Earth Science Frontiers
基金
中央高校基本业务费项目(2652017458)
中国石油天然气股份有限公司重大项目(2014A-02)。
关键词
鄂尔多斯盆地
三叠纪
原型盆地
层序地层学
盆山耦合
Ordos Basin
Triassic
prototype basin
sequence stratigraphy
basin-mountain coupling
